Make sure to drop the references taken to the larb devices during
probe on probe failure (e.g. probe deferral) and on driver unbind.

Fixes: b17336c55d89 ("iommu/mediatek: add support for mtk iommu generation one HW")
Cc: stable@vger.kernel.org	# 4.8
Cc: Honghui Zhang <honghui.zhang@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/iommu/mtk_iommu_v1.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index de9153c0a82f..44b965a2db92 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -648,8 +648,10 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev)
 		struct platform_device *plarbdev;
 
 		larbnode = of_parse_phandle(dev->of_node, "mediatek,larbs", i);
-		if (!larbnode)
-			return -EINVAL;
+		if (!larbnode) {
+			ret = -EINVAL;
+			goto out_put_larbs;
+		}
 
 		if (!of_device_is_available(larbnode)) {
 			of_node_put(larbnode);
@@ -659,11 +661,14 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev)
 		plarbdev = of_find_device_by_node(larbnode);
 		if (!plarbdev) {
 			of_node_put(larbnode);
-			return -ENODEV;
+			ret = -ENODEV;
+			goto out_put_larbs;
 		}
 		if (!plarbdev->dev.driver) {
 			of_node_put(larbnode);
-			return -EPROBE_DEFER;
+			put_device(&plarbdev->dev);
+			ret = -EPROBE_DEFER;
+			goto out_put_larbs;
 		}
 		data->larb_imu[i].dev = &plarbdev->dev;
 
@@ -675,7 +680,7 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev)
 
 	ret = mtk_iommu_v1_hw_init(data);
 	if (ret)
-		return ret;
+		goto out_put_larbs;
 
 	ret = iommu_device_sysfs_add(&data->iommu, &pdev->dev, NULL,
 				     dev_name(&pdev->dev));
@@ -697,12 +702,17 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev)
 	iommu_device_sysfs_remove(&data->iommu);
 out_clk_unprepare:
 	clk_disable_unprepare(data->bclk);
+out_put_larbs:
+	for (i = 0; i < MTK_LARB_NR_MAX; i++)
+		put_device(data->larb_imu[i].dev);
+
 	return ret;
 }
 
 static void mtk_iommu_v1_remove(struct platform_device *pdev)
 {
 	struct mtk_iommu_v1_data *data = platform_get_drvdata(pdev);
+	int i;
 
 	iommu_device_sysfs_remove(&data->iommu);
 	iommu_device_unregister(&data->iommu);
@@ -710,6 +720,9 @@ static void mtk_iommu_v1_remove(struct platform_device *pdev)
 	clk_disable_unprepare(data->bclk);
 	devm_free_irq(&pdev->dev, data->irq, data);
 	component_master_del(&pdev->dev, &mtk_iommu_v1_com_ops);
+
+	for (i = 0; i < MTK_LARB_NR_MAX; i++)
+		put_device(data->larb_imu[i].dev);
 }
 
 static int __maybe_unused mtk_iommu_v1_suspend(struct device *dev)
-- 
2.49.1